(cross-posted at my site, Xenocrypt's site.)
In a previous post, I mapped when women's suffrage failed in the U.S. House in 1915. For this post, I thought I'd map the (House) passage of the Eighteenth Amendment: Prohibition.
Here's a link to the vote on Govtrack. The prohibition amendment was sent to the states by a vote of 282 to 128--a landslide in absolute terms, but relatively close given the margin required to pass a Constitutional amendment.
The 65th House of Representatives was closely divided between Republicans and Democrats. 208 Democrats, 201 Republicans (one "independent"), 3 Progressives, 1 Socialist, and 1 Prohibitionist voted on the Eighteenth Amendment.
Remarkably enough, the major parties split in nearly identical ratios on this issue, with 140 Democrats and 138 Republicans supporting Prohibition, and 64 Democrats and 62 Republicans in opposition. Even the 3 Progressives followed the pattern and split 2-1.
Here's the map. Once again, I used the historical Congressional shapefiles (by Jeffrey B. Lewis, Brandon Devine, Lincoln Pritcher, and Kenneth Martis), along with Govtrack.